Rollable display device and a method of manufacturing the same

ABSTRACT

A rollable display device including: a support module; a display module disposed on the support module and including a display area and a non-display area adjacent to the display area; and a resin layer disposed between the support module and the display module, the display module including a display panel including a plurality of pixels, the support module including: a plurality of support bars extending in a first direction and arranged in a second direction crossing the first direction, wherein the support bars are spaced apart from each other; and a plurality of hinges disposed between the support bars and coupled with the support bars disposed adjacent thereto, and wherein each of the support bars is rotatably coupled with the hinges with respect to a driving axis extending in the first direction and the driving axis penetrates the display panel when viewed in a cross-section.

CROSS-REFERENCE TO RELATED APPLICATION

This U.S. non-provisional patent application claims priority under 35U.S.C. § 119 to Korean Patent Application No. 10-2021-0010888, filed onJan. 26, 2021, the disclosure of which is incorporated by referenceherein in its entirety.

1. TECHNICAL FIELD

The present disclosure relates to a display device. More particularly,the present disclosure relates to a rollable display device and a methodof manufacturing the rollable display device.

2. DESCRIPTION OF THE RELATED ART

A display device is an output device for presentation of information invisual form. Multimedia devices, such as a television, a mobile phone, atablet computer, a notebook computer, and a game unit, include a displaydevice to provide images to a user. As technology advances, varioustypes of display devices are being developed. For example, variousflexible display devices, which are capable of being curved, folded orrolled, have been developed. The flexible display devices can be easy tocarry and convenient.

For example, a rollable display device, which can be rolled up like anewspaper, has superior portability than a non-rollable display device.

A display module of a rollable display device has a structure in whichvarious components are stacked. However, stress generated when therollable display device is rolled may damage the components of thedisplay module. In addition, a surface quality of the display module maydeteriorate depending on a support structure supporting the rollabledisplay device.

SUMMARY

The present disclosure provides a rollable display device capable ofincreasing a surface quality and a reliability of a display module.

The present disclosure provides a method of manufacturing the rollabledisplay device with increased reliability.

An embodiment of the present disclosure provides a rollable displaydevice including: a support module; a display module disposed on thesupport module and including a display area and a non-display areaadjacent to the display area; and a resin layer disposed between thesupport module and the display module, the display module including adisplay panel including a plurality of pixels, the support moduleincluding: a plurality of support bars extending in a first directionand arranged in a second direction crossing the first direction, whereinthe support bars are spaced apart from each other; and a plurality ofhinges disposed between the support bars and coupled with the supportbars disposed adjacent thereto, and wherein each of the support bars isrotatably coupled with the hinges with respect to a driving axisextending in the first direction and the driving axis penetrates thedisplay panel when viewed in a cross-section.

A neutral plane of the display module may be defined in the displaypanel at a same position as the driving axis when viewed in thecross-section.

The resin layer may have a modulus equal to or greater than about 1 kPaand equal to or less than about 50 MPa.

Each of the support bars may include a coupling portion, the couplingportion may be inserted into a coupling recess in each of the hinges,and the coupling portion of each of the support bars may move within thecoupling recess.

The support module may further include a sub-support bar extending inthe first direction and disposed between a pair of the support bars, andthe sub-support bar may be coupled to the hinges connected to the pairof the support bars.

Each of the support bars may have a width in the second direction andthe widths of the support bars may be different from each other.

A difference in width between the support bars adjacent to each othermay be constant.

The support module may include a rolling area and a peripheral areaadjacent to the rolling area, the support module may be in a flat stateor in a rolled state depending on whether the support module is rolledwith respect to a rolling axis spaced apart from the driving axis, alength of the rolling area of the support module defined in the seconddirection in the flat state may satisfy the following Equation 1 of

${L = {{x \cdot a} + \frac{x \cdot {b\left( {x - 1} \right)}}{2}}},$

an outer diameter of the support module in the rolled state may satisfythe following Equation 2 of D=(√{square root over (2)}+1)·{a+(5+x)b}, Lmay denote the length of the rolling area of the support module, D maydenote the outer diameter of the support module, x may denote a numberof the support bars, a may denote a smallest width among the widths ofthe support bars, and b may denote a difference in width between thesupport bars adjacent to each other.

The support module may further include a plurality of bonding portionsfilled in a separation space between the support bars.

The bonding portions may be provided integrally with the resin layer.

The support bars may include surfaces that are in contact with thebonding portions, and at least a portion of the surfaces may include acurved surface.

The support module may further include a plurality of magnets insertedinto at least one of the support bars.

The magnets may be spaced apart from the display area in a plane view.

The display module may further include: a window disposed on the displaypanel; and a protective layer disposed between the display panel and theresin layer, wherein a neutral plane may be defined between a lowersurface of the display panel and an upper surface of the display panel.

The rollable display device may further include: a flexible circuitboard electrically connected to the display panel; and a main circuitboard disposed on a lower surface of the support module, the supportbars including: first support bars overlapping the display area andconnected to each other; and a second support bar connected to one firstsupport bar disposed at an outermost position in the second directionamong the first support bars, and wherein the main circuit board isspaced apart from the first support bars in a plane view and overlapsthe second support bar, and the flexible circuit board surrounds atleast a portion of the second support bar and is electrically connectedto the main circuit board.

Widths of the first support bars, which are defined in the seconddirection, may increase as a distance from the second support bardecreases.

The rollable display device may further include a case spaced apart fromthe display area and accommodating the flexible circuit board and themain circuit board.

An embodiment of the present disclosure provides a method ofmanufacturing a rollable display device, the method including: disposinga plate on a mold; disposing a support module on the mold, wherein aspace is provided between the support module and the plate; filling aresin in the space; curing the resin to form a resin layer; separatingthe plate from the resin layer; and disposing a display module on theresin layer from which the plate is separated.

The method may further include coating a primer on the support modulebefore the disposing of the support module.

The method may further include disposing a spacer supporting the supportmodule on the plate after the disposing of the plate.

An embodiment of the present disclosure provides a rollable displaydevice including: a support module comprising a plurality of supportbars and a plurality of hinges; a display module disposed on the supportmodule; and a resin layer disposed between the display module and thesupport module, wherein the plurality of support bars extended in afirst direction and arranged in a second direction crossing the firstdirection, and the plurality of hinges connecting adjacent support barsto each other, and wherein widths of the support bars are different fromeach other.

Widths of the support bars may increase from a first side of the displaymodule to a second side of the display module.

The support module may further include a plurality of sub-support barsconnected to the hinges.

The resin layer may overlap a gap between adjacent support bars.

According to the above, the rollable display device includes the supportmodule that provides the flat upper surface, and thus, the surfacequality of the rollable display device is improved.

In addition, as the driving axis of the support module is defined topenetrate through the display panel when viewed in cross-section, thereliability of the display module is increased.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present disclosure will becomereadily apparent by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1A is a perspective view showing a rollable display device in aflat state according to an embodiment of the present disclosure;

FIG. 1B is a perspective view showing the rollable display device in arolled state according to an embodiment of the present disclosure;

FIG. 2A is an exploded perspective view showing some components of therollable display device shown in FIG. 1A;

FIG. 2B is a cross-sectional view taken along a line I-I′ shown in FIG.1A;

FIG. 3 is a cross-sectional view showing a display module before andafter being rolled according to an embodiment of the present disclosure;

FIG. 4 is a cross-sectional view showing a display panel according to anembodiment of the present disclosure;

FIG. 5 is a perspective view showing some components of a rollabledisplay device according to an embodiment of the present disclosure;

FIG. 6 is a cross-sectional view taken along a line II-II′ shown in FIG.5 according to an embodiment of the present disclosure;

FIG. 7A is a cross-sectional view showing some components of a rollabledisplay device in a flat state corresponding to a partial area shown inFIG. 5;

FIG. 7B is a cross-sectional view showing some components of a rollabledisplay device in a rolled state corresponding to a partial area shownin FIG. 5;

FIG. 8A is a perspective view showing some components of a rollabledisplay device in a flat state according to an embodiment of the presentdisclosure;

FIG. 8B is a perspective view showing some components of a rollabledisplay device in a rolled state according to an embodiment of thepresent disclosure;

FIG. 9A is a cross-sectional view taken along a line III-III′ shown inFIG. 8A to show some components of a rollable display device accordingto an embodiment of the present disclosure;

FIG. 9B is a cross-sectional view taken along a line IV-IV′ shown inFIG. 8B to show some components of a rollable display device accordingto an embodiment of the present disclosure;

FIG. 10A is a cross-sectional view taken along a line III-III′ shown inFIG. 8A to show some components of a rollable display device accordingto an embodiment of the present disclosure;

FIG. 10B is a cross-sectional view taken along a line IV-IV′ shown inFIG. 8B to show some components of a rollable display device accordingto an embodiment of the present disclosure;

FIG. 11A is a plan view showing a portion of a support module accordingto an embodiment of the present disclosure;

FIG. 11B is an enlarged view showing an area shown in FIG. 11A;

FIG. 12A is a side view showing a support module in a rolled stateaccording to an embodiment of the present disclosure;

FIG. 12B is a perspective view showing some components of a rollabledisplay device in a flat state according to an embodiment of the presentdisclosure;

FIG. 13 is a side view showing a support module in a rolled state moduleaccording to an embodiment of the present disclosure;

FIG. 14A is a scanning electron microscope (SEM) color image showingsurface quality characteristics of a comparative example;

FIG. 14B is a SEM color image showing surface quality characteristics ofan example of an embodiment of the present disclosure;

FIG. 14C is a black and white image of the SEM image shown in FIG. 14A;

FIG. 14D is a black and white image of the SEM image shown in FIG. 14B;

FIG. 15A is a graph showing surface quality characteristics of acomparative example;

FIG. 15B is a graph showing surface quality characteristics of anexample of an embodiment of the present disclosure;

FIG. 16 is a flowchart showing a method of manufacturing a rollabledisplay device according to an embodiment of the present disclosure;

FIGS. 17A, 17B, and 17C are perspective views showing a method ofmanufacturing a rollable display device according to an embodiment ofthe present disclosure;

FIGS. 18A, 18B, 18C and 18D are cross-sectional views showing a methodof manufacturing a rollable display device according to an embodiment ofthe present disclosure;

FIG. 19 is a cross-sectional view showing a method of manufacturing arollable display device according to an embodiment of the presentdisclosure;

FIGS. 20A, 20B, and 20C are perspective views showing a method ofmanufacturing a rollable display device according to an embodiment ofthe present disclosure; and

FIG. 20D is a cross-sectional view showing a method of manufacturing arollable display device according to an embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure may be variously modified and realized in manydifferent forms, and thus specific embodiments will be illustrated inthe drawings and described in detail hereinbelow. However, the presentdisclosure should not be limited to the specific disclosed forms, and beconstrued to include all modifications, equivalents, or replacementsincluded in the spirit and scope of the present disclosure.

In the present disclosure, it will be understood that when an element orlayer is referred to as being “on”, “connected to” or “coupled to”another element or layer, it can be directly on, connected or coupled tothe other element or layer or intervening elements or layers may bepresent.

Like numerals may refer to like elements throughout. In the drawings,the thickness, ratio, and dimension of components may be exaggerated foreffective description of the technical content.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another element. Thus, a first element discussed belowcould be termed a second element. As used herein, the singular forms,“a”, “an” and “the” are intended to include the plural forms as well,unless the context clearly indicates otherwise.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as shown in the figures.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the an to which this disclosure belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

It will be further understood that the terms “includes” and/or“including”, when used in this specification, specify the presence ofstated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof.

Hereinafter, a rollable display device and a method of manufacturing therollable display device of the present disclosure will be explained indetail with reference to the accompanying drawings.

FIGS. 1A and 1B are perspective views showing a rollable display deviceDD according to an embodiment of the present disclosure. FIG. A is aperspective view showing a rollable display device DD in a flat state inwhich the rollable display device DD is not rolled according to anembodiment of the present disclosure. FIG. 1B is a perspective viewshowing the rollable display device DD in a rolled state in which therollable display device DD is rolled in a clockwise direction accordingto an embodiment of the present disclosure.

An upper surface of the rollable display device DD may be substantiallyparallel to a plane formed by a first direction DR1 and a seconddirection DR2 crossing the first direction DR1. The rollable displaydevice DD may have a thickness in a third direction DR3 perpendicular tothe plane formed by the first direction DR1 and the second directionDR2. The rollable display device DD may have a hexahedron shape when therollable display device DD is in the flat state, however, the shape ofthe rollable display device DD should not be limited to the hexahedronshape.

Upper (or front) and lower (or rear) surfaces of each member may bedescribed with respect to a surface substantially parallel to the firstdirection DR1 and the second direction DR2. The front and rear surfacesare opposite to each other in the third direction DR3, and a normal linedirection of each of the front and rear surfaces may be substantiallyparallel to the third direction DR3.

In the following descriptions, the expression “in a plane view” may meana state of being viewed from the above of components, e.g., a state ofbeing viewed in the third direction DR3. In the following descriptions,the expression “in a cross-section” or “in a side view” may mean a stateof being viewed in the first direction DR1 or the second direction DR2.In the following descriptions, a “thickness direction” may be adirection substantially parallel to the third direction DR3.

A separation distance between the front and rear surfaces of each memberin the third direction DR3 may correspond to a thickness or a height ofeach member. Directions indicated by the first, second, and thirddirections DR1, DR2, and DR3 may be relative to each other and may bechanged to other directions.

Referring to FIG. 1A, the rollable display device DD may include adisplay module DM, a support module SM, and a resin layer LR (refer toFIG. 28). The rollable display device DD may be rolled with respect toan imaginary rolling axis. For example, the rollable display device DDmay be rolled in a clockwise or counterclockwise direction along arolling axis. The display module DM may be flexible.

The display module DM may provide an image to a user through a displaysurface DM-IS. The display surface DM-IS may be substantially parallelto the surface formed by the first direction DR1 and the seconddirection DR2. The display surface DM-IS may include a display area DAand a non-display area NDA. The display area DA may be an area in whichthe image is displayed, and the non-display area NDA may be an area inwhich the image is not displayed. The non-display area NDA may surroundthe display area DA, however, it should not be limited thereto orthereby. The non-display area NDA may be adjacent to only one side ofthe display area DA.

The display module DM may include a plurality of pixels generating theimage displayed through the display area DA. Each of the pixels mayinclude a light emitting element and a transistor electrically connectedto the light emitting element. The pixels may include an organic lightemitting diode as an example of the light emitting element. The pixelsmay be disposed in the display area DA, however, they should not belimited thereto or thereby. According to an embodiment of the presentdisclosure, some of the pixels may be disposed in the non-display areaNDA.

The support module SM may be disposed under the display module DM. Thesupport module SM may support a lower surface and a side surface of thedisplay module DM. The support module SM may support the display moduleDM and substantially simultaneously may roll the display module DM witha predetermined curvature.

The support module SM may include a rolling area RA and a peripheralarea SA. The rolling area RA may be rolled with respect to the imaginaryrolling axis. The peripheral area SA may be adjacent to one side of therolling area RA, and a circuit board that applies electrical signals tothe display module DM may be disposed in the peripheral area SA. Forexample, the peripheral area SA may be adjacent to a short side of therolling area RA; however, the present disclosure is not limited theretoand the peripheral area SA may be adjacent to a long side of the rollingarea RA.

The resin layer LR (refer to FIG. 2B) may be disposed between thesupport module SM and the display module DM. The resin layer LR maycombine the display module DM with the support module SM. The resinlayer LR may provide a flat upper surface, and thus, may increase asurface quality of the display module DM when the display module DM isrolled. This will be described in detail later.

Referring to FIG. 1B, the support module SM may include a plurality ofsupport bars SP and a plurality of hinges HG. The support module SM mayfurther include a plurality of sub-support bars SP-S. Hereinafter, therollable display device DD that includes the sub-support bars SP-S willbe described as an example, however, the present disclosure should notbe limited thereto or thereby. According to an embodiment of the presentdisclosure, the sub-support bars SP-S may be omitted.

The support bars SP may extend in a direction substantially parallel tothe imaginary rolling axis. The support bars SP may extend in the firstdirection DR1 and may be arranged in the second direction DR2. Thesupport bars SP may include long sides extending in the first directionDR1 and short sides extending in the second direction DR2. The longsides of the support bars SP may be parallel to the short side of therolling area RA, and the short sides of the support bars SP may beparallel to the long side of the rolling area RA, however, the presentdisclosure is not limited thereto.

Each of the support bars SP may include a metal material. However, thematerial for the support bars SP should not be particularly limited aslong as the support bars SP may support the display module DM.

Each of the hinges HG may be disposed between the support bars SPadjacent to each other and may combine the adjacent support bars SP toeach other. In other words, a hinge HG may be disposed between a pair ofthe support bars SP. Each of the hinges HG may be disposed adjacent tothe short sides of the support bars SP in the second direction DR2 andmay be coupled with the support bars SP adjacent thereto.

The hinges HG may be spaced apart from each other with the support barSP interposed therebetween and coupled therewith in the second directionDR2. The hinges HG respectively coupled with one side and the other sideof one support bar SP may be spaced apart from each other in the firstdirection DR1. In other words, a first hinge HG connecting two adjacentsupport bars SP to each other may be disposed on a first side of therolling area RA, and a second hinge HG connecting the two adjacentsupport bars SP to each other may be disposed on a second side of therolling area RA opposite the first side.

Each of the support bars SP may be coupled with the hinges HG to rotatewith respect to a driving axis extending in the first direction DR1. Thesupport bars SP may be rotated at a predetermined angle with respect tothe driving axis. In the following descriptions, the driving axis may bean imaginary fixed rotation axis that serves as a center of rotationwhen the support bar is rotated at a predetermined angle. The supportmodule SM may be rolled with a predetermined radius of curvature withrespect to the rolling axis spaced apart from the driving axis by thesupport bars SP rotatably coupled with the hinges HG. The radius of thecurvature of the rolled support module SM may be changed depending onstructures of the support bars SP and the hinges HG.

Each of the sub-support bars SP-S may extend in the same direction asthe direction in which the support bars SP extend. The sub-support barsSP-S may include long sides extending in the first direction DR1 andshort sides extending in the second direction DR2.

Each of the sub-support bars SP-S may be disposed between the supportbars SP adjacent to each other. The sub-support bars SP-S may bedisposed adjacent to the long sides of the support bars SP. Thesub-support bars SP-S and the support bars SP may be alternatelyarranged with each other in the second direction DR2.

Each of the sub-support bars SP-S may be coupled with the hinges HGspaced apart from each other in the first direction DR1. The supportbars SP may move after being coupled with the hinges HG, and thesub-support bars SP-S may be fastened after being coupled with thehinges HG. In other words, the sub-support bars SP-S may be fixed inplace by the hinges HG.

The sub-support bars SP-S may be disposed between the support bars SPspaced apart from each other and may support the display module DM. Thesub-support bars SP-S may be disposed between the support bars SP spacedapart from each other and may increase the surface quality of thedisplay module DM when the display module DM is rolled.

FIG. 2A is an exploded perspective view showing some components of therollable display device DD shown in FIG. 1A, and FIG. 2B is across-sectional view taken along a line I-I′ shown in FIG. 1A.

Referring to FIGS. 2A and 2B, the rollable display device DD may furtherinclude a flexible circuit board CF, a main circuit board MB, and a caseCS. The flexible circuit board CF and the main circuit board MB mayapply electrical signals to a display panel DP included in the displaymodule DM.

The flexible circuit board CF may be disposed on the support module SM.The flexible circuit board CF may overlap the peripheral area SA of thesupport module SM.

The flexible circuit board CF may be electrically connected to thedisplay panel DP and the main circuit board MB. One end of the flexiblecircuit board CF may be electrically connected to an area of the displaypanel DP overlapping the non-display area NDA. The other end of theflexible circuit board CF may be electrically connected to the maincircuit board MB.

A driving circuit may be mounted on the flexible circuit board CF. Theflexible circuit board CF may transmit a signal from the main circuitboard MB to the driving circuit and may transmit a signal from thedriving circuit to the display panel DP. However, according to anembodiment of the present disclosure, the driving circuit may be mountedon the display panel DP or the main circuit board MB.

The flexible circuit board CF may include a base layer that is flexible.The flexible circuit board CF may have flexibility, may surround aportion of the support module SM, and may be connected to the displaypanel DP and the main circuit board MB. The flexible circuit board CFmay electrically connect the display panel DP disposed on an uppersurface of the support module SM to the main circuit board MB disposedon a lower surface of the support module SM.

The flexible circuit board CF may be provided in plural, and theflexible circuit boards CF may be arranged in one direction, and each ofthe flexible circuit boards CF may be electrically connected to thedisplay panel DP. FIG. 2A shows the flexible circuit boards CF arrangedin the first direction DR1, however, the present disclosure should notbe limited thereto or thereby. The flexible circuit board CF may beprovided in a singular number, or some of the flexible circuit boards CFmay overlap each other to form a pair, however, they should not beparticularly limited.

Referring to FIG. 2B, the support bars SP of the support module SM mayinclude a plurality of first support bars SP-a disposed in the rollingarea RA and a second support bar SP-b disposed in the peripheral areaSA. The first support bars SP-a may overlap the display area DA and maybe connected to each other via the sub-support bars SP-S. The secondsupport bar SP-b may be connected to the first support bar SP-a, whichis disposed at an outermost position in the second direction DR2, amongthe first support bars SP-a connected to each other. In other words, thefirst support bar SP-a disposed directly adjacent to the peripheral areaSA may be connected to the second support bar SP-b.

The main circuit board MB may be disposed on the lower surface of thesupport module SM. The main circuit board MB may overlap the peripheralarea SA and may be disposed on a lower surface of the second support barSP-b. The second support bar SP-b may directly contact the main circuitboard MB. The main circuit board MB may be spaced apart from the firstsupport bars SP-a when viewed in a plane view and may be disposed tooverlap the second support bar SP-b.

A signal controller may be mounted on the main circuit board MB. Thesignal controller may apply a control signal to the display panel DP viathe flexible circuit board CF.

The case CS may overlap the peripheral area SA of the support module SM.The case CS may be spaced apart from the display area DA when viewed ina plane view. The case CS may protect the flexible circuit board CF andthe main circuit board MB from external impacts and foreign substances.

The case CS may accommodate the flexible circuit board CF and the maincircuit board MB. As an example, the case CS may include an upper coverand a lower cover coupled with the upper cover. The upper cover and thelower cover coupled with the upper cover may provide an inner space inwhich the flexible circuit board CF and the main circuit board MB areaccommodated. The case CS should not be particularly limited as long asthe case CS may accommodate the flexible circuit board CF and the maincircuit board MB.

The display module DM may be disposed on the support module SM tooverlap the rolling area RA of the support module SM. The display moduleDM may include a protective layer PF, the display panel DP, and a windowWM.

The display panel DP may provide the image to the user through thedisplay module DM. The display panel DP may be a light-emitting typedisplay panel, however, it should not be particularly limited. Forinstance, the display panel DP may be an organic light emitting displaypanel or an inorganic light emitting display panel. A light emittinglayer of the organic light emitting display panel may include an organiclight emitting material. A light emitting layer of the inorganic lightemitting display panel may include a quantum dot or a quantum rod.Hereinafter, the organic light emitting display panel will be describedas the display panel DP.

The display panel DP may include a display substrate DS, a displayelement layer DL, and an encapsulation layer TFE. The display substrateDS, the display element layer DL, and the encapsulation layer TFE may besequentially stacked one on another.

The display substrate DS may include a semiconductor layer, a pluralityof insulating layers, and a plurality of conductive layers. The displaysubstrate DS may form a scan driving circuit, signal lines, and a pixelcontrol circuit. The display substrate DS may receive electrical signalsfrom the flexible circuit board CF and the main circuit board MB, whichare electrically connected thereto.

The display element layer DL may overlap the display area DA of thedisplay module DM and may be disposed on the display substrate DS. Thedisplay element layer DL may include the light emitting element and mayemit a light to the display surface DM-IS of the display module DM. Asan example, the display element layer DL may include the organic lightemitting diode.

The encapsulation layer TFE may be disposed on the display element layerDL to cover the display element layer DL. The encapsulation layer TFEmay include a plurality of thin films. Some thin films may protect thelight emitting element, and some thin films may be disposed to increasea light efficiency.

The window WM may be disposed on the display panel DP. The window WM mayprotect the display panel DP from external scratches and externalimpacts.

The window WM may include an optically transparent insulating material.The image generated on the display panel DP may be provided to the userafter passing through the window WM. As an example, the window WM mayinclude a polymer substrate, a plastic substrate, a thin glasssubstrate, or the like. The window WM may have a single-layer ormulti-layer structure.

The window WM may include at least one of optical films. The opticalfilms may include at least one of a polarizing film a diffusing film, aprotective film, and the like. The window WM may further include afunctional coating layer, such as an anti-fingerprint coating layer oran anti-reflective coating layer.

The protective layer PF may be disposed under the display panel DP. Theprotective layer PF may have a single-layer or multi-layer structure. Asan example, the protective layer PF may be a layer including at leastone plastic film. For instance, the plastic film may include oneselected from the group consisting of polyethersulfone (PES),polyacrylate, polyetherimide (PEI), polyethylenenaphthalate (PEN),polyethyleneterephthalate (PET), polyphenylene sulfide (PPS),polyarylate, polyimide (PI), polycarbonate (PC), poly aryleneethersulfone and a combination thereof. However, this is merely anexample, and the material for the protective layer PF should not beparticularly limited as long as the protective layer PF may have theflexibility and may protect a lower portion of the display panel DP.

The resin layer LR may be disposed between the support module SM and thedisplay module DM. The resin layer LR may be in contact with the uppersurface of the support module SM and the lower surface of the displaymodule DM. The resin layer LR may be in contact with the support bars SPincluded in the support module SM. For example, the resin layer LR maybe in direct contact with the first and second support bars SP-a andSP-b.

The resin layer LR may cover an upper surface of the first support barsSP-a disposed in the rolling area RA. The resin layer LR may cover a gapor a boundary between the first support bars SP-a spaced apart from eachother, and thus, may provide a flat upper surface to the display moduleDM. Accordingly, the surface quality of the display module DM disposedon the resin layer LR may be increased.

The resin layer LR may cover at least a portion of an upper surface ofthe second support bar SP-b disposed in the peripheral area SA, however,it should not be limited thereto or thereby. According to an embodimentof the present disclosure, the resin layer LR may entirely cover theupper surface of the second support bar SP-b.

The resin layer LR may include an elastomer material. The resin layer LRincluding the elastomer material may be deformed by an external forceapplied thereto and may be easily returned to its original state whenthe external force is removed. The resin layer LR may have a modulusequal to or greater than about 1 kPa and equal to or less than about 50MPa. When the modulus of the resin layer LR is less than about 1 kPa,the shape of the resin layer LR may not be returned to its originalstate and may be easily deformed or damaged after the external force isremoved. When the modulus of the resin layer LR is greater than about 50MPa, the flexibility of the resin layer LR may be deteriorated, and as aresult, the resin layer LR may be broken when being rolled.

FIG. 3 is a cross-sectional view showing the display module DM beforeand after being rolled according to an embodiment of the presentdisclosure. Descriptions of the display module DM with reference toFIGS. 2A and 2B may be applied to the display module DM shown in FIG. 3.

Referring to FIG. 3, the display module DM may further include adhesivelayers AD1 and AD2. A first adhesive layer AD1 may be disposed betweenthe protective layer PF and the display panel DP. A second adhesivelayer AD2 may be disposed between the display panel DP and the windowWM. Each of the first adhesive layer AD1 and the second adhesive layerAD2 may include an optical clear adhesive, an optical clear resin, or apressure sensitive adhesive, which has a light transmitting property.

The components of the display module DM having the multi-layer structuremay be rolled with a predetermined radius of curvature. As shown in FIG.3, when observing an enlarged cross-section of the curved display moduleDM, a certain portion of the cross-section may be stretched by a tensilestress, and a certain portion of the cross-section may be compressed bya compressive stress. The compressive stress and the tensile stress maybe generated relatively.

A plane in which the compressive stress and the tensile stress are inequilibrium on a cross-section may be a neutral plane. The compressivestress may increase as a distance from a center of the curvature in theneutral plane decreases, and the tensile stress may increase as adistance from the center of the curvature in the neutral planeincreases.

A position of the neutral plane may be influenced by a material, astructure, a thickness, a modulus, and a Poisson's ratio of the stackedcomponents. According to the position of the neutral plane, somecomponents of the stack structure may receive the tensile stress whenbeing rolled, and some components of the stack structure may receive thecompressive stress when being rolled. As the position of the neutralplane of the display module DM is adjusted, the display module DM may beprevented from being damaged by an external stress.

According to an embodiment of the present disclosure, the neutral planeNP of the display module DM may be in the display panel DP. In otherwords, the neutral plane NP of the display module DM may be locatedbetween a lower surface of the display panel DP and an upper surface ofthe display panel DP. When the display module DM is designed to allowthe neutral plane NP to be in the display panel DP, the display panel DPmay be prevented from being damaged by the stress applied thereto whenbeing rolled.

The resin layer LR (refer to FIG. 2B) and the display module DM, whichare disposed on the support module SM, may be a stack module. Thethickness and the modulus of the resin layer LR (refer to FIG. 2B) mayexert an influence on the neutral plane of the stack module, however,the influence may be small. In other words, a position of the neutralplane of the stack module including the resin layer LR (refer to FIG.2B) and the display module DM and a position of the neutral plane of thedisplay module DM may be substantially the same as each other or may bewithin a margin of error. As an example, the neutral plane of thedisplay module DM and the neutral plane of the stack module may be inthe display panel DP, and the positions of the neutral planes may besubstantially the same as each other, or a difference between thepositions of the neutral planes may be within the margin of error.

FIG. 4 is a cross-sectional view showing the display panel DP accordingto an embodiment of the present disclosure. The cross-sectional view ofthe display panel DP shown in FIG. 4 may correspond to one pixelincluded in the display area DA of the display module DM.

Referring to FIG. 4, the display panel DP may include the displaysubstrate DS, the display element layer DL, and the encapsulation layerTFE. The display substrate DS, the display element layer DL, and theencapsulation layer TFE may be sequentially stacked in the thirddirection DR3.

The display substrate DS may include a base layer BL, a barrier layerBR, a buffer layer BF, a plurality of insulating layers ENC1, ENC2, andENC3, a switching transistor, and a driving transistor TFT-D. Thebarrier layer BR, the buffer layer BF, and the insulating layers ENC1,ENC2, and ENC3 may include one of an inorganic layer and an organiclayer.

The base layer BL may be a layer on which a plurality of transistors isdisposed. The base layer BL may be a silicon substrate, a plasticsubstrate, or a glass substrate and may be a stack structure including aplurality of insulating layers. The base layer BL may be flexible.

The barrier layer BR may be disposed on the base layer BL. The barrierlayer BR may prevent impurities present in the base layer BL or moistureentering from outside from being diffused to the transistors. Theimpurities may be gas or sodium generated by a thermal decomposition ofthe base layer BL.

The buffer layer BF may be disposed on the barrier layer BR. Asemiconductor pattern ALD of the driving transistor TFT-D may bedisposed on the buffer layer BF. The buffer layer BF may increase anadhesion between the base layer BL and the semiconductor pattern ALD.

The driving transistor TFT-D may include the semiconductor pattern ALD,a control electrode GED, an input electrode SED, and an output electrodeDED. The semiconductor pattern ALD may include amorphous silicon,polycrystalline silicon, or a metal oxide semiconductor.

A first insulating layer ENC1 may be disposed on the semiconductorpattern ALD. The first insulating layer ENC1 may cover a portion of thesemiconductor pattern ALD. The first insulating layer ENC1 may includeat least one organic layer or inorganic layer. As an example, theinorganic layer may be one of a silicon nitride layer and a siliconoxide layer, however, it should not be limited thereto or thereby.

The control electrode GED may be disposed on the first insulating layerENC1. The control electrode GED may be a gate electrode of the drivingtransistor TFT-D. A control electrode of the switching transistor may bedisposed on the first insulating layer ENC1.

A second insulating layer ENC2 may be disposed on the first insulatinglayer ENC1 and may cover the control electrode GED. The secondinsulating layer ENC2 may include at least one organic layer orinorganic layer. As an example, the inorganic layer may be one of thesilicon nitride layer or the silicon oxide layer, however, it should notbe limited thereto or thereby.

The input electrode SED and the output electrode DED may be disposed onthe second insulating layer ENC2. The input electrode SED may be asource electrode of the driving transistor TFT-D and the outputelectrode DED may be a drain electrode of the driving transistor TFT-D.A input electrode and an output electrode of the switching transistormay be disposed on the second insulating layer ENC2.

The input electrode SED and the output electrode DED may be electricallyconnected to the semiconductor pattern ALD respectively via a firstcontact hole CH1 and a second contact hole CH2, which are formed throughthe first insulating layer ENC1 and the second insulating layer ENC2.

A third insulating layer ENC3 may be disposed on the second insulatinglayer ENC2 and may cover the input electrode SED and the outputelectrode DED. The third insulating layer ENC3 may include at least oneorganic layer or inorganic layer. In particular, the third insulatinglayer ENC3 may include an organic layer to provide a flat surface.

Each of the second insulating layer ENC2 and the third insulating layerENC3 may be an interlayer insulating layer. The interlayer insulatinglayer may insulate a conductive pattern disposed thereunder from aconductive pattern disposed thereon.

The display element layer DL may be disposed on the third insulatinglayer ENC3. The display element layer DL may include a pixel definitionlayer PDL and a light emitting element EL. The light emitting element ELmay include a first electrode AE, a hole control layer HCL, a lightemitting layer EML, an electron control layer ECL, and a secondelectrode CE.

The display element layer DL may include light emitting areas PXA and anon-light-emitting area NPXA adjacent to the light emitting areas PXA.The light emitting area PXA may be an area from which a light isemitted. The non-light-emitting area NPXA may surround the lightemitting area PXA.

The first electrode AE may be disposed on the third insulating layerENC3. The first electrode AE may be electrically connected to the outputelectrode DED of the driving transistor TFT-D via a third contact holeCH3 formed through the third insulating layer ENC3.

The pixel definition layer PDL may be provided with an opening OPtherethrough. A portion of the first electrode AE may be exposed throughthe opening OP of the pixel definition layer PDL. The opening OP of thepixel definition layer PDL may correspond to the light emitting areasPXA. In the present embodiment, the light emitting areas PXA maycorrespond to areas of the first electrode AE exposed through theopening OP.

The hole control layer HCL may be commonly disposed over the lightemitting area PXA and the non-light-emitting area NPXA. The hole controllayer HCL may be commonly formed in the pixels.

The light emitting layer EML may be disposed on the hole control layerHCL. The light emitting layer EML may be disposed in an areacorresponding to the opening OP of the pixel definition layer PDL. Inother words, the light emitting layer EML may be provided in a patternto correspond to the opening OP, however, it should not be limitedthereto or thereby. According to an embodiment of the presentdisclosure, the light emitting layer EML may be commonly disposed overthe pixels.

The light emitting layer EML may generate a light. As an example, thelight emitting layer EML may generate a white light or a blue light. Thelight emitting layer EML may include an organic material or an inorganicmaterial as its light emitting material. As an example, the lightemitting layer EML may include at least one of an organic compound andan organometallic compound as its light emitting material, however, itshould not be limited thereto or thereby. According to an embodiment ofthe present disclosure, the light emitting layer EML may include aquantum dot as its light emitting material.

The electron control layer ECL may be disposed on the light emittinglayer EML. The second electrode CE may be disposed on the electroncontrol layer ECL. The electron control layer ECL and the secondelectrode CE may be commonly disposed over the light emitting area PXAand the non-light-emitting area NPXA.

The encapsulation layer TFE may encapsulate the display element layerDL. As an example, the encapsulation layer TFE may directly cover thesecond electrode CE. However, the display panel DP may further include acapping layer disposed on the display element layer DL to cover thesecond electrode CE, and in this case, the encapsulation layer TFE maydirectly cover the capping layer.

The encapsulation layer TFE may include an organic layer and aninorganic layer. In FIG. 4, the encapsulation layer TFE having asingle-layer structure is shown, however, the encapsulation layer TFEmay have a multi-layer structure in which the inorganic layer and theorganic layer are sequentially stacked. For example, the encapsulationlayer TFE may have a structure in which the organic layer is disposedbetween the inorganic layers.

The display module DM may further include an input sensing layerdisposed on the encapsulation layer TFE. The input sensing layer maysense various types of external inputs, such as a user's hand, heat,light, etc. The input sensing layer may include a plurality ofconductive layers and a plurality of insulating layers. The inputsensing layer may be disposed directly on the encapsulation layer TFE ormay be disposed on the encapsulation layer TFE with an adhesive filminterposed therebetween.

The neutral plane NP (refer to FIG. 3) of the display module DM may beinfluenced by a thickness, a material, a modulus, and an arrangementstructure of each of various components included in the display panelDP. The position of the neutral plane NP (refer to FIG. 3) of thedisplay module DM may be changed depending on each component included inthe display panel DP. In other words, the neutral plane NP (refer toFIG. 3) may move in the third direction DR3 depending on the number ofcomponents included in the display panel DP. As an example, eachcomponent of the display panel DP and the display module DM may bedesigned so that the neutral plane NP (refer to FIG. 3) of the displaymodule DM is adjacent to the encapsulation layer TFE included in thedisplay panel DP, or each component of the display panel DP and thedisplay module DM may be designed so that the neutral plane NP (refer toFIG. 3) of the display module DM is in the encapsulation layer TFE.

FIG. 5 is a perspective view showing some components of the rollabledisplay device according to an embodiment of the present disclosure.FIG. 5 shows the support module SM and the resin layer LR disposed onthe support module SM. For the convenience of explanation, the resinlayer LR is shown as a transparent layer. FIG. 6 is a cross-sectionalview taken along a line II-II′ shown in FIG. 5 according to anembodiment of the present disclosure. FIGS. 7A and 7B are enlargedcross-sectional views showing an area AA shown in FIG. 5.

Referring to FIGS. 5 and 6, the support module SM may include thesupport bars SP, the hinges HG, and the sub-support bars SP-S, and theresin layer LR may be disposed on the support module SM. Thedescriptions of the above-described elements may be equally applied tothe same elements.

The support bars SP may extend in the first direction DR1 and may bearranged in the second direction DR2 crossing the first direction DR1.The support bars SP may be spaced apart from each other at predeterminedintervals. As an example, the support bars SP adjacent to each other maybe spaced apart from each other with the sub-support bar SP-S interposedtherebetween in the second direction DR2, however, they should not belimited thereto or thereby. According to an embodiment of the presentdisclosure, the support bars SP may be partially in contact with thesupport bars SP adjacent to each other in the second direction DR2 whenthe support module SM is in the flat state.

The support bars SP may include the first support bars SP-a disposed inthe rolling area RA and the second support bar SP-b disposed in theperipheral area SA. One first support bar SP-a (e.g., first support barSPn of FIG. 5) disposed at an outermost position among the first supportbars SP-a along the second direction DR2 may be connected to the secondsupport bar SP-b by the hinges HG. The second support bar SP-b may bewider than each of the first support bars SP-a, however, the presentdisclosure is not limited thereto.

The first support bars SP-a may include n (n is a natural number) numberof support bars. The n first support bars SP-a may be arranged in thesecond direction DR2. Hereinafter, for the convenience of explanation,in the flat state, the first support bar SP-a among the first supportbars SP-a disposed farthest from the second support bar SP-b in thesecond direction DR2 is referred to as a No. 1 support bar SP1, and thefirst support bar SP-a among the first support bars SP-a disposedclosest to the second support bar SP-b in the second direction DR2 isreferred to as an No. n support bar SPn.

The first support bars SP-a disposed in the rolling area RA may havedifferent widths from each other. In the present disclosure, the widthof the support bar may be a length of a short side, which extends in thesecond direction DR2, of the support bar. The widths of the firstsupport bars SP-a may gradually increase as a distance from the secondsupport bar SP-b decreases.

For example, the No. 1 support bar SP1 may have a first width W1, andthe No. n support bar SPn may have an n-th width Wn. A differencebetween the widths of the other first support bars SP-a and the firstwidth W1 may increase as a distance in the second direction DR2 from thefirst support bar SP1 increases. The first width W1 may be the smallestwidth among the widths of the first support bars SP-a, and the n-thwidth Wn may be the largest width among the widths of the first supportbars SP-a.

Referring to FIG. 6, each of the first support bars SP-a may include afirst portion SP-1, a second portion SP-2 bent from one side of thefirst portion SP-1, and a third portion SP-3 bent from the other side ofthe first portion SP-1. The second portion SP-2 and the third portionSP-3 may face each other in the first direction DR1. The second portionSP-2 and the third portion SP-3 may be higher than the first portionSP-1 in the third direction DR3.

The display module DM (refer to FIG. 1A) may be disposed between thesecond portions SP-2 and the third portions SP-3 of the first supportbars SP-a. An upper surface of the first portion SP-1 may face the lowersurface of the display module DM disposed on the support module SM. Aninner surface of the second portion SP-2 may face one side surface ofthe display module DM disposed on the support module SM. An innersurface of the third portion SP-3 may face the other side surface of thedisplay module DM, which is opposite to the one side surface of thedisplay module DM. In other words, the inner surfaces of the second andthird portions SP-2 and SP-3 may face opposite side surfaces of thedisplay module DM and fix the display module DM in place.

The support module SM may have a thickness TT corresponding to adistance from a lowermost surface to an uppermost surface of the firstsupport bars SP-a, which is defined in the third direction DR3. Thelowermost surface of the first support bar SP-a may be a lower surfaceof the first portion SP-1 of the first support bar SP-a. The uppermostsurface of the first support bar SP-a may be an upper surface SP-2-U ofthe second portion SP-2 and an upper surface SP-3-U of the third portionSP-3.

Each of the hinges HG may connect the first support bars SP-a adjacentto each other. The hinges HG may be disposed in spaces between the firstsupport bars SP-a coupled with the hinges HG. As an example, the hingesHG may be disposed between the second portions SP-2 spaced apart fromeach other or between the third portions SP-3 spaced apart from eachother of the first support bars SP-a adjacent to each other in thesecond direction DR2. In this case, the hinges HG may be parallel toeach other.

However, according to an embodiment of the present disclosure, each ofthe hinges HG may be disposed on an outer surface of the support barsSP, may be coupled with the support bars SP, and may protrude from theouter surface of the support bars SP. In the alternative, each of thehinges HG may be disposed on an inner surface of the support bars SP.The shape of the hinges HG should not be particularly limited as long asthe hinges HG may be coupled with the support bars SP and may move thesupport bars SP coupled therewith with respect to the driving axis DX(refer to FIGS. 7A and 7B).

The resin layer LR may cover the upper surfaces of the first portionsSP-1 of the first support bars SP-a and the upper surfaces of thesub-support bars SP-S. In other words, the resin layer LR may cover thearea between the second portions SP-2 and the third portions SP-3 of thefirst support bars SP-a. The upper surface of the support module SM,which corresponds to the upper surfaces of the first portions SP-1 andthe upper surfaces of the sub-support bars SP-S may be uneven due to adistance and a step difference between the first support bars SP-a andthe sub-support bars SP-S. Since the resin layer LR of the presentdisclosure covers the upper surfaces of the first portions SP-1 of thefirst support bars SP-a and the upper surfaces of the sub-support barsSP-S, a flat upper surface LR-U may be provided to the display moduleDM, and the surface quality of the display module DM may be increased.

The upper surface of the display module DM (refer to FIG. 2B) disposedon the resin layer LR may meet with the upper surface SP-2-U of thesecond portion SP-2 of the first support bars SP-a and the upper surfaceSP-3-U of the third portion SP-3 of the first support bars SP-a whenviewed in a cross-section. In other words, the thickness of the displaymodule DM may be substantially the same as a height between the flatupper surface LR-U of the resin layer LR and the upper surface SP-2-U ofthe second portion SP-2. In other words, a top of the display module DMmay be at the same level as the upper surface SP-2-U of the secondportion SP-2 of the first support bars SP-a and the upper surface SP-3-Uof the third portion SP-3 of the first support bars SP-a.

FIG. 7A is a cross-sectional view showing a portion of the supportmodule in the flat state, and FIG. 7B is a cross-sectional view showingthe support module of FIG. 7A in the rolled state. FIGS. 7A and 7B showone hinge HG among the hinges HG and two first support bars SP-a coupledwith the one hinge HG.

Referring to FIG. 7A, each of the first support bars SP-a may include acoupling portion CC. The coupling portion CC may protrude in the firstdirection DR1 from an outer surface of the second portion SP-2 and thethird portion SP-3 of the first support bar SP-a substantially parallelto a surface formed by the second direction DR2 and the third directionDR3. For example, the coupling portion CC may have the shape of acylinder. However, the shape of the coupling portion CC should not belimited thereto or thereby.

The coupling portion CC may include the same material as the secondportion SP-2 and the third portion SP-3 of the first support bar SP-aand may be provided integrally with the second portion SP-2 and thethird portion SP-3, however, it should not be limited thereto orthereby. According to an embodiment of the present disclosure, thecoupling portion CC may include a material different from that of thesecond portion SP-2 and the third portion SP-3 of the first support barSP-a.

The hinge HG may be provided with a coupling recess HH. The couplingportion CC of the first support bar SP-a may be inserted into thecoupling recess HH of the hinge HG, and thus, the first support bar SP-amay be coupled with the hinge HG. One hinge HG may be provided with twocoupling recesses HH. The coupling portions CC of the support bars SP-aadjacent to each other may be inserted into the coupling recesses HH,respectively. For example, the coupling portion CC of a first supportbar may be inserted into a first coupling recess of a hinge HG and thecoupling portion CC of a second support bar adjacent to the firstsupport bar may be inserted into a second coupling recess of the hingeHG. The coupling portion CC of the first support bar SP-a, which iscoupled with the hinge HG, may move along a shape of the coupling recessHH.

The hinge HG may include a coupling part CN coupled with the sub-supportbar SP-S (refer to FIG. 6). The coupling part CN may overlap thesub-support bar SP-S (refer to FIG. 6) when viewed in the firstdirection DR1. The hinge HG and the sub-support bar SP-S (refer to FIG.6) may be coupled with each other by a screw or by a recess and aprotrusion, which have shapes corresponding to each other. The shape ofthe coupling part CN should not be particularly limited as long as thehinge HG and the sub-support bar SP-S (refer to FIG. 6) may be coupledwith each other by the coupling part CN.

Referring to FIG. 7B, when the support module SM is rolled, each of thefirst support bars SP-a may be rotated with respect to the driving axisDX extending in the first direction DR1. For example, the first supportbars SP-a may move along the coupling recess HH to correspond to theshape of the coupling recess HH. Each of the first support bars SP-a maymove from the driving axis DX by a predetermined arc of a circle with apredetermined radius of curvature RR with respect to the driving axisDX. The radius of curvature RR may be a straight line from the drivingaxis DX to a center of the coupling portion CC when viewed in a sideview.

The driving axis DX of the support module SM may penetrate the displaymodule DM disposed on the support module SM when viewed incross-section. For example, the driving axis DX may penetrate thedisplay panel DP when viewed in a cross-section. The driving axis DX ofthe support module SM may be at the same position as that of the neutralplane NP (refer to FIG. 3) of the display module DM when viewed incross-section. In other words, a height from the lower surface of thedisplay module DM disposed on the support module SM to the neutral planeNP (refer to FIG. 3) of the display module DM may be substantially thesame as a height from the lower surface of the display module DM to thedriving axis DX.

In a stack structure in which two or more layers having different modulifrom each other are stacked, a neutral plane of the stack structure maybe adjacent to a layer having a relatively high modulus with respect toa center of the stack structure when viewed in a cross-section.

The first support bars SP-a may be rotated with respect to the drivingaxes DX respectively defined in the first support bars SP-a, and thesupport module SM may be rolled with respect to the rolling axis spacedapart from the driving axes DX by the first support bars SP-a, which arerotated with respect to the driving axes DX. An imaginary plane NP-Sconnecting the driving axes DX may be a plane whose length is notchanged in the support module SM. As such, the driving axes DX may befixed in place. The modulus of the support module SM may be greater thanthe modulus of each stack structure included in the display module DM.Accordingly, the neutral plane of the rollable display device DD may beprovided at a position that is closer to the imaginary plane NP-Sconnecting the driving axes DX of the support module SM than the neutralplane NP (refer to FIG. 3) of the display module DM.

The display module DM and the support module SM may be designed suchthat the neutral plane NP (refer to FIG. 3) of the display module DM isprovided at the same position as that of the driving axes DX when viewedin cross-section. Since the neutral plane of the rollable display deviceDD, which is adjacent to the driving axes DX of the support module SM,is close to or coincides with the neutral plane NP (refer to FIG. 3) ofthe display module DM, a degree to which the display module DM isdamaged by a strain in the rolling operation may be reduced. As thedamage of the display module DM is reduced, the reliability of therollable display device DD may be increased.

For example, the neutral plane NP (refer to FIG. 3) of the displaymodule DM may be provided in the display panel DP by controlling athickness and a modulus of each component of the protective layer PF,the display panel DP, and the window WM of the display module DM. Whenthe display module DM is rolled, each component of the display panel DPadjacent to the neutral plane NP (refer to FIG. 3) of the display moduleDM when viewed in cross-section may receive a relatively smaller strainthan that applied to the window WM and the protective layer PF, whichare relatively far from the neutral plane NP (refer to FIG. 3) of thedisplay module DM. Accordingly, the light emitting element and thecircuits included in the display panel DP may not be damaged or may beless damaged by the strain.

In addition, the driving axis DX of the support module SM may be changeddepending on a thickness, an arrangement, and a shape of each component,such as the support bars SP, the hinges HG, etc. As shown in FIGS. 7Aand 7B, the driving axis DX may be provided to penetrate the hinge HGwhen viewed in a side view, however, it should not be limited thereto orthereby.

FIG. 8A is a perspective view showing a portion of the support module SMand the resin layer LR in the flat state according to an embodiment ofthe present disclosure. FIG. 8B is a perspective view showing a portionof the support module SM and the resin layer LR in the rolled stateaccording to an embodiment of the present disclosure. FIGS. 8A and 8Bshow one hinge HG among the hinges HG and one sub-support bar SP-S andtwo first support bars SP-a, which are coupled with the hinge HG.

Referring to FIGS. 8A and 8B, the first support bars SP-a adjacent toeach other may be spaced apart from each other by a predetermineddistance. As an example, one first support bar SP-a and another firstsupport bar SP-a adjacent to the one first support bar SP-a may bespaced apart from each other with the sub-support bar SP-S interposedtherebetween. The first support bars SP-a may be spaced apart from thesub-support bar SP-S by a first distance T1 in the second direction DR2.As an example, the first distance T1 may be equal to or less than about1 mm. However, the first distance T1 may be equal to or greater thanabout 1 mm without being limited thereto or thereby. The first distanceT1 may correspond to a gap between the one first support bar SP-a andthe sub-support bar SP-S, for example.

FIG. 9A is a cross-sectional view taken along a line III-III′ shown inFIG. 8A to show the support module SM and the resin layer LR accordingto an embodiment of the present disclosure. FIG. 9B is a cross-sectionalview taken along a line IV-IV′ shown in FIG. 8B to show the supportmodule SM and the resin layer LR according to an embodiment of thepresent disclosure.

Referring to FIG. 9A, the resin layer LR may cover the upper surface ofthe sub-support bar SP-S and the upper surfaces of the first supportbars SP-a. The resin layer LR may cover a gap between the sub-supportbar SP-S and the first support bars SP-a adjacent to the sub-support barSP-S to provide the flat upper surface.

Referring to FIG. 9B, when the support module SM is rolled, the distancebetween the sub-support bar SP-S and the first support bars SP-aadjacent to the sub-support bar SP-S may increase compared with that inthe flat state as a distance from the resin layer LR increases. Theresin layer LR may cover the gap, and thus, the surface quality of thedisplay module DM disposed on the resin layer LR may be increased.However, when the support module SM is rolled, the stress may beconcentrated at portions 10 of the resin layer LR, which are adjacent tocorners of the first support bars SP-a.

FIG. 10A is a cross-sectional view taken along a line III-III′ shown inFIG. 8A to show a support module SM and a resin layer LR according to anembodiment of the present disclosure. FIG. 10B is a cross-sectional viewtaken along a line IV-IV′ shown in FIG. 8B to show the support module SMand the resin layer LR according to an embodiment of the presentdisclosure. The support module SM shown in FIGS. 10A and 10B havesubstantially the same configurations as the support module SM shown inFIGS. 9A and 9B except some components.

Referring to FIGS. 10A and 10B, the support module SM may furtherinclude a bonding portion LM filled in a space between a sub-support barSP-S and a first support bar SP-a adjacent to the sub-support bar SP-Sin the second direction DR2. The bonding portion LM may be in contactwith one surface of the sub-support bar SP-S and one surface of thefirst support bar SP-a, which faces the one surface of the sub-supportbar SP-S.

The bonding portion LM may include a resin. The bonding portion LM mayinclude an elastomer material. The bonding portion LM may have a modulusequal to or less than about 50 MPa. In detail, the bonding portion LMmay have a modulus equal to or greater than about 1 kPa and equal to orless than about 50 MPa. When the modulus of the bonding portion LM isless than about 1 kPa, the shape of the bonding portion LM, which isdeformed by the rolling operation, may not be returned to its originalstate and may be easily deformed or damaged. When the modulus of thebonding portion LM is greater than about 50 MPa, the flexibility of thebonding portion LM may be deteriorated, and as a result, the bondingportion LM may be broken when being rolled.

The bonding portion LM may include the same material as that of theresin layer LR. As shown in FIG. 10A, the bonding portion LM may be incontact with a portion of the resin layer LR. As shown in FIG. 10B, thebonding portion LM may be provided integrally with the resin layer LR.In this case, the resin layer LR may be formed to fill the gap betweenthe sub-support bar SP-S and the first support bar SP-a adjacent to thesub-support bar SP-S.

The bonding portion LM and the resin layer LR may be substantiallysimultaneously formed through the same process, however, they should notbe limited thereto or thereby. According to an embodiment of the presentdisclosure, the bonding portion LM and the resin layer LR may beseparately formed through processes that are sequentially performed. Asan example, the bonding portion LM may be formed through a separateresin coating and curing process before the resin layer LR is formed.After the bonding portion LM is formed, the resin layer LR may be formedthrough a resin coating and curing process.

Referring to FIG. 10B, the bonding portion LM may be in contact with theresin layer LR and corners of the first support bars SP-a. When thesupport module SM is rolled, the bonding portion LM may be tensioned asa gap between the sub-support bar SP-S and the first support bars SP-aadjacent to the sub-support bar SP-S increases. The bonding portion LMmay prevent the stress from being concentrated at portions 20 of theresin layer LR adjacent to the corners of the first support bars SP-a,and thus, the resin layer LR may be prevented from being damaged.

FIG. 11A is a plan view showing a portion of a support module accordingto an embodiment of the present disclosure. FIG. 11B is an enlarged viewshowing an area BB shown in FIG. 11A. FIG. 11A shows one sub-support barSP-S and two first support bars SP-a and SP-a′ adjacent to thesub-support bar SP-S. For the convenience of explanation, the two firstsupport bars SP-a and SP-a′ having different shapes from each other areshown, however, the first support bars included in one support module SMmay have the same shape as each other.

Referring to FIG. 11A, the first support bars SP-a and SP-a′ may includea plurality of surfaces that is in contact with the bonding portion LM.Each of the first support bars SP-a and SP-a′ may include a firstsurface 100 substantially parallel to a long side of the first supportbar SP-a and SP-a′, which extends in the first direction DR1, and asecond surface 200 bent from the first surface 100. The first surface100 and the second surface 200 may be in contact with the bondingportion LM. The first support bars SP-a and SP-a′ may each include athird surface 300 facing one surface of the sub-support bar SP-S, andthe third surface 300 may be substantially parallel to the first surface100. The second surface 200 may be connected to the first surface 100and the third surface 300. According to an embodiment of the presentdisclosure, an angle (01) between the second surface 200 and the thirdsurface 300 of the first support bar SP-a′ may be a right angle.

Referring to FIG. 11B, according to an embodiment of the presentdisclosure, the first support bar SP-a may further include a fourthsurface 400 that is in contact with the bonding portion LM and connectedto the second surface 200 and the third surface 300. The fourth surface400 may be bent from the second surface 200. In other words, the fourthsurface 400 may be slanted with respect to the second surface 200 andthe third surface 300. An angle (02) between the second surface 200 andthe fourth surface 400 may be an obtuse angle. The angle (02) may begreater than the angle (01). The fourth surface 400 may be a surfacethat is substantially parallel to one direction or that includes acurved surface. The portion of the bonding portion LM that is in contactwith the support bar SP-a may be prevented from being damaged by thefirst support bar SP-a including at least one curved surface that is incontact with the bonding portion LM.

FIGS. 12A and 13 are side views showing support modules SM in a rolledstate according to an embodiment of the present disclosure. FIG. 12B isa perspective view showing some components of the support module SMshown in FIG. 12A. In FIGS. 12A, 12B, and 13, the same referencenumerals denote the same elements, and thus, the descriptions of theabove-described elements may be equally applied to the same elements.

Referring to FIGS. 12A and 13, in the support module SM in the rolledstate, the first support bar SP-a, which is disposed closest to therolling axis RX, among the first support bars SP-a in the rolling areaRA may correspond to the No. 1 support bar SP1 disposed farthest fromthe second support bar SP-b shown in FIG. 5, and the first support barSP-a disposed farthest from the rolling axis RX may correspond to theNo. n support bar SPn disposed closest to the second support bar SP-b.

The support module SM may be rolled with respect to the imaginaryrolling axis RX. The rolling axis RX may be spaced apart from thedriving axis DX and may extend in the first direction DR1. As anexample, FIG. 12A shows the support module SM rolled in an octagonalshape when viewed in a side view, however, the support module SM shouldnot be limited thereto or thereby. According to an embodiment of thepresent disclosure, the support module SM may be rolled in a polygonalshape whose number of sides is smaller than 8 or greater than 8.

Referring to FIGS. 12A and 128, the support module SM may furtherinclude magnets MG inserted into at least some first support bars SP-aamong the first support bars SP-a. FIG. 12B is a perspective viewshowing some first support bars SP-a each into which the magnets MG areinserted.

FIG. 12A shows the support module SM in which the magnet MG is insertedinto some support bars among the first support bars SP-a. Since thefirst support bars SP-a have different widths from each other, the widthof the some support bars may not be sufficient to accommodate the magnetMG, and thus, some support bars may not include the magnet MG. As anexample, referring to FIG. 12A, among the first support bars SP-a rolledin the octagonal shape, the No. 1 support bar SP1 to a No. 8 supportbar, which are rolled closest to the rolling axis RX, may not includethe magnet MG, and a No. 9 support bar to the No. n support bar SPn mayinclude the magnet MG, however, they should not be limited thereto orthereby. In other words, the support bars closest to the rolling axis RXmay not include the magnet MG. According to an embodiment of the presentdisclosure, all the first support bars SP-a may include the magnet MG ormay include a smaller number of magnets MG than that shown in FIG. 12A.

In the rolled state, some magnets MG among the magnets MG respectivelyinserted into the first support bars SP-a may be substantially parallelto each other in one direction. As an example, referring to FIG. 12A,four first support bars SP-a may be stacked from the rolling axis RX tothe one direction to be substantially parallel to each other. Themagnets MG inserted into the first support bars SP-a, which are stackedin the one direction to be substantially parallel to each other, may besubstantially parallel to each other. For example, in the support moduleSM rolled in the octagonal shape, the magnet MG included in the No. 9support bar, the magnet MG included in a No. 17 support bar, and themagnet MG included in a No. 25 support bar may be substantially parallelto each other in the one direction. For example, the magnet MG includedin the No. 9 support bar, the magnet MG included in the No. 17 supportbar, and the magnet MG included in a No. 25 support bar may besubstantially parallel to each other in the third direction DR3 in therolled state.

According to an embodiment of the present disclosure, the support moduleSM may further include the bonding portion LM (refer to FIG. 10B) thatis tensioned in the rolling operation, and the bonding portion LM mayhave a property of returning to its original state before beingtensioned by a restoration force. According to an embodiment of thepresent disclosure, since the support module SM may further include themagnets MG inserted into at least some support bars among the firstsupport bars SP-a, the support module SM may be stably rolled by anattractive force between the magnets MG.

Referring to FIG. 12B, the magnets MG may be spaced apart from thedisplay area DA of the display module DM when viewed in a plane view.One first support bar SP-a may include at least one magnet MG. As anexample, FIG. 12B shows two magnets MG inserted into one first supportbar SP-a. The magnets MG included in the one first support bar SP-a maybe spaced apart from each other in the first direction DR1.

Referring to FIG. 13, the widths of the first support bars SP-a disposedin the rolling area RA may vary depending on the radius of curvature inthe rolling operation. The widths of the first support bars SP-a mayincrease as a distance from the rolling axis RX increases. The firstwidth W1 of the No. 1 support bar SP1 disposed closest to the rollingaxis RX may be the smallest among the widths of the first support barsSP-a. The n-th width Wn of the No. n support bar SPn disposed farthestfrom the rolling axis RX may be the largest among the widths of thefirst support bars SP-a.

The radius of curvature in the rolling operation may increase as adistance from the rolling axis RX increases. As the radius of curvatureincreases, the width of the first support bar SP-a may be relativelylarge. The first width W1 of the No. 1 support bar SP1 rolled at a firstradius of curvature R1 may be smaller than a second width W2 of a No. 2support bar SP2 rolled at a second radius of curvature R2 greater thanthe first radius of curvature R1.

According to an embodiment of the present disclosure, a length, an outerdiameter, and a thickness of the rolling area RA of the support moduleSM may have a correlation with the number and width of the support barsSP-a arranged in the rolling area RA.

In the present disclosure, the length of the rolling area RA of thesupport module SM may correspond to a length of the rolling area RA inthe second direction DR2 crossing the direction of the rolling axis RXof the support module SM in the flat state. Referring to FIG. 5, thelength of the rolling area RA of the support module SM may correspond toa total length from the No. 1 support bar SP1 to the No. n support barSPn arranged along the second direction DR2 in the flat state. Thelength of the rolling area RA of the support module SM may satisfy thefollowing Equation 1.

$\begin{matrix}{L = {{x \cdot a} + \frac{x \cdot {b\left( {x - 1} \right)}}{2}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

In Equation 1, L denotes the length of the rolling area RA of thesupport module SM. In Equation 1, x denotes the number of the firstsupport bars SP-a included in the support module SM, a denotes thesmallest width among the widths of the first support bars SP-a, and bdenotes a difference in width between the first support bars SP-aadjacent to each other. As an example, a may be the first width W1 ofthe No. 1 support bar SP1 having the smallest width, and b may be thedifference in width between the first width W1 of the No. 1 support barSP1 and the second width W2 of the No. 2 support bar SP2 adjacent to theNo. 1 support bar SP1.

The outer diameter OD of the support module SM may correspond to anoutermost diameter of the support module SM in the rolled state. Theouter diameter OD of the support module SM may correspond to a lengthfrom a lower surface of one support bar to a lower surface of anothersupport bar, which are disposed farthest from the rolling axis RX andface each other in the third direction DR3, among the rolled firstsupport bars SP-a. The outer diameter OD of the support module SM may besubstantially the same as an outer diameter of the rollable displaydevice DD in the rolled state. The outer diameter OD of the supportmodule SM may satisfy the following Equation 2.

D=(√{square root over (2)}+1)·{a+(5+x)b}  Equation 2

In Equation 2, D denotes the outer diameter OD of the support module SM.In Equation 2, x, a, and b may be substantially the same as x, a, and bin Equation 1, respectively.

Details on the thickness TT of the support module SM described withreference to FIG. 6 may be equally applied to the thickness TT of thesupport module SM of FIG. 13. The thickness TT of the support module SMmay satisfy the following Equation 3.

T=4(√{square root over (2)}+1)b  Equation 3

In Equation 3, T denotes the thickness TT of the support module SM. InEquation 3, x, a, and b may be substantially the same as x, a, and b inEquation 1, respectively.

An embodiment of the present disclosure provides a rollable displaydevice DD including: a support module SM; a display module DM disposedon the support module SM and including a display area DA and anon-display area NDA adjacent to the display area DA; and a resin layerLR disposed between the support module SM and the display module DM, thedisplay module DM including a display panel DP including a plurality ofpixels, the support module SM including: a plurality of support barsSP-a extending in a first direction DR1 and arranged in a seconddirection DR2 crossing the first direction DR1, wherein the support barsSP-a are spaced apart from each other; and a plurality of hinges HGdisposed between the support bars SP-a and coupled with the support barsSP-a disposed adjacent thereto, and wherein each of the support barsSP-a is rotatably coupled with the hinges HG with respect to a drivingaxis DX extending in the first direction DR1.

FIGS. 14A and 14B are scanning electron microscope (SEM) color imagesshowing surface quality characteristics of a comparative example and anexample of an embodiment of the present disclosure. FIG. 14C is an imageobtained by converting FIG. 14A to black and white, and FIG. 14D is animage obtained by converting FIG. 14B to black and white. FIGS. 15A and15B are graphs showing the surface quality characteristics of thecomparative example and the example of the embodiment of the presentdisclosure.

FIG. 14A is the SEM color image showing the surface qualitycharacteristics of the comparative example (FIG. 14C is the black andwhite SEM image of FIG. 14A), and FIG. 14B is the SEM color imageshowing the surface quality characteristics of the example of theembodiment of the present disclosure (FIG. 14D is the black and whiteSFM image of FIG. 14B). The comparative example corresponds to arollable display device in which a resin layer is not disposed between asupport module and a display module, and the example of the embodimentof the present disclosure corresponds to the rollable display device DDin which the resin layer LR is disposed between the support module SMand the display module DM. In each of the images shown in FIGS. 14A and14B, a degree of difference in height with respect to a referencesurface corresponding to zero (0) of a bar graph shown on the right isexpressed in various colors. In FIGS. 14C and 14D, the degree ofdifference in height with respect to the reference surface correspondingto zero (0) of a bar graph shown on the right is expressed in variousshadows

Referring to FIGS. 14A and 14B, the reference surface is expressed as agreen color (referring to FIGS. 14C and 14D, the reference surface isexpressed as relatively light gray shade), a portion protruding in thethird direction DR3 from the reference surface is expressed as a redcolor, and a portion recessed in the third direction DR3 from thereference surface is expressed as a blue color (referring to FIGS. 14Cand 14D, the portion protruding or recessed from the reference surfaceis expressed as relatively dark black shade). Since an area of the greencolor (or an area of the light gray shade shown FIG. 14C and FIG. 14D)corresponding to the reference surface increases, an area of theprotruded or recessed portion may decrease, and the surface qualitycharacteristics of the rollable display device may be superior.

When comparing FIG. 14A with FIG. 14B (or comparing FIG. 14C with FIG.14D), it is observed that the area of the red portion protruded from thereference surface or the area of the blue portion recessed from thereference surface in FIG. 14B (or the area of the portion protruded orrecessed from the reference surface expressed as the dark black shade inFIG. 14D) is smaller than those in FIG. 14A (or those in FIG. 14C). Thismay mean that the surface quality characteristics of the rollabledisplay device according to the embodiment example shown in FIG. 14B (orshown in FIG. 14D) is relatively superior.

In addition, it is observed that a maximum protruded portion or amaximum recessed portion in the rollable display device of thecomparative example has a height of about 300 μm and a maximum protrudedportion or a maximum recessed portion in the rollable display device ofthe example of the embodiment of the present disclosure has a height ofabout 25 μm relative to the reference surface. Accordingly, the rollabledisplay device of the example of the embodiment of the presentdisclosure and the rollable display device of the comparative examplemay have a difference in height of about 250 μm or more in the protrudedor recessed portion.

FIGS. 15A and 15B are graphs showing a protruded or recessed degree ofthe rollable display device when viewed in a side view formed by thesecond direction DR2 and the third direction DR3. A horizontal axis ofthe graphs may correspond to the second direction DR2, and a verticalaxis of the graphs may correspond to the third direction DR3. Theflatter the shape shown in the graphs, the better the surface qualitycharacteristics.

FIG. 15A is the graph showing the surface quality characteristics of thecomparative example, and FIG. 15B is the graph showing the surfacequality characteristics of the example of the embodiment of the presentdisclosure. Descriptions of the comparative example and the example ofthe embodiment of the present disclosure are the same as those describedwith reference to FIGS. 14A and 14B.

Referring to FIGS. 15A and 15B, when compared with the comparativeexample, the rollable display device of the example of the embodiment ofthe present disclosure has relatively few protruded or recessed portionsrelative to the reference surface, and the protruded or recessed degreeis also relatively small. This may mean that the surface qualitycharacteristics of the rollable display device of the example of theembodiment of the present disclosure is relatively superior.

Accordingly, the surface quality characteristics of the rollable displaydevice including the resin layer that provides the flat upper surfacebetween the support module and the display module may be increased. Therollable display device having the increased surface qualitycharacteristics may provide the image with superior quality to the user.

FIG. 16 is a flowchart showing a method of manufacturing the rollabledisplay device according to an embodiment of the present disclosure. Themanufacturing method of the rollable display device may includedisposing a plate on a mold (S1), disposing the support module on themold to define a separation space between the support module and theplate (S2), filling a resin in the separation space (S3), curing thefilled resin to form the resin layer (S4), separating the plate from theresin layer (S5), and disposing the display module on the resin layerfrom which the plate is separated (S6).

FIGS. 17A to 17C are perspective views showing the manufacturing methodof the rollable display device according to an embodiment of the presentdisclosure. FIGS. 18A to 18D are cross-sectional views showing themanufacturing method of the rollable display device according to anembodiment of the present disclosure. The cross-sectional views show thecross-section viewed from the side view formed by the first directionDR1 and the third direction DR3.

FIG. 17A shows the disposing of a plate GL on a mold MD (S1). The moldMD may include a support part BS that supports the plate GL disposed onthe mold MD. FIG. 17A shows the support part BS extending in the firstdirection DR1 and supporting some areas adjacent to an edge of the plateGL, however, the support part BS may entirely support a lower surface ofthe plate GL, and a shape of the support part BS should not beparticularly limited as long as the support part BS may support theplate GL.

An upper surface of plate GL disposed on the mold MD may be flat. As theresin layer LR is formed on the flat upper surface of the plate GL, anupper surface of the resin layer LR may be flat. As an example, theplate GL may be a glass plate whose upper surface is flat. Since theresin layer LR is formed on the glass plate, the flatness of the uppersurface of the resin layer LR may be improved. However, the plate GLshould not be limited thereto or thereby.

FIG. 17B shows the disposing of the support module SM on the mold MD todefine the separation space between the support module and the plate GL(S2). Detailed descriptions about the support module SM may besubstantially the same as described above. The support module SM may bedisposed to allow the upper surface of the support module SM to face theupper surface of the plate GL. In other words, the support module SM maybe disposed such that the lower surface of the support module SM isviewed from the outside.

The manufacturing method of the rollable display device may furtherinclude disposing a protective film on the upper surface of the plate GLbefore the support module SM is provided on the plate GL. Accordingly,the plate GL with the protective film on the upper surface thereof maybe disposed on the mold MD, and the resin layer LR may be formed on theprotective film. The protective film may be a film forming theprotective layer PF of the display module DM. After the plate GL isremoved from the protective film, components of the display module DMmay be disposed on the protective film. The protective film may protectsome components of the display module DM, which are to be disposed onthe protective film during a manufacturing process of the rollabledisplay device. In addition, the protective film may allow the supportmodule SM on which the resin layer LR (refer to FIG. 18C) is formed tobe easily separated from the plate GL, however, it should not be limitedthereto or thereby. The disposing of the protective film may be omitted.

FIG. 17C shows the filling of the resin in the separation space betweenthe plate GL and the support module SM (S3). The resin may be filled inthe separation space along a direction 110 to which the separation spaceis exposed. Referring to FIG. 17C, the separation space between theplate GL and the support module SM may be exposed to the seconddirection DR2 when viewed in the side view formed by the first directionDR1 and the third direction DR3, and the resin may be filled in theseparation space along the second direction DR2.

The mold MD may further include outer walls surrounding the supportmodule SM disposed thereon. The outer walls may prevent the resin fromleaking to the outside of the support module SM and the mold MD duringthe filling of the resin.

FIG. 18A shows the disposing of the support module SM on the mold MD todefine the separation space SS between the support module SM and theplate GL (S2). The support module SM may be disposed to allow the uppersurface SM-U of the support module SM to face the upper surface of theplate GL. The separation space SS may be provide between the uppersurface SM-U of the support module SM and the upper surface of the plateGL. The upper surface SM-U of the support module SM may correspond tothe upper surface of the first portions SP-1 (refer to FIG. 6) of thefirst support bars SP-a.

The support module SM may have a shape including a portion bent from theupper surface SM-U of the support module SM. The bent portion of thesupport module SM may correspond to the second portion SP-2 (refer toFIG. 6) and the third portion SP-3 (refer to FIG. 6) of the firstsupport bars SP-a. The upper surfaces SP-2-U and SP-3-U (refer to FIG.6) of the second and third portions SP-2 and SP-3 (refer to FIG. 6) maybe supported by the mold MD.

The separation space SS formed between the support module SM and theplate GL may be filled with the resin. The separation space SS may havea first thickness D1 in the third direction DR3. The first thickness D1may correspond to the thickness of the resin layer LR formed by thefollowing processes.

The manufacturing method of the rollable display device may furtherinclude coating a primer on the upper surface SM-U of the support moduleSM before the support module SM is provided on the plate GL. The primermay include a material that increases an adhesion between the supportmodule SM and the resin. The adhesion between the upper surface SM-U ofthe support module SM and the resin filled in the separation space SSmay increase by the primer. The resin provided in an area where theprimer is not coated may be easily removed compared with the resinprovided in an area where the primer is coated, and an area to which theresin is attached and an area to which the resin is not attached may bedistinguished by the primer.

FIG. 18B shows the forming of the resin layer LR. The resin layer LR maybe formed by filling the resin in the separation space SS and curing thefilled resin (S3 and S4).

The bonding portion LM (refer to FIG. 10B) of the support module SM maybe substantially simultaneously formed with the resin layer LR. Theresin may be filled in the separation space between the first supportbars SP-a (refer to FIG. 10B) and in the separation space SS between theplate GL and the support module SM by adjusting an amount of the resin,and then, the resin layer LR and the bonding portion LM (refer to FIG.10B) may be substantially simultaneously formed through the curingprocess, however, it should not be limited thereto or thereby. Accordingto an embodiment of the present disclosure, after the support module SMis disposed to allow the upper surface SM-U thereof to be viewed fromthe outside, the bonding portion LM (refer to FIG. 10B) may be formed bycoating and curing the resin on the upper surface SM-U of the supportmodule SM, and then, the resin layer LR may be formed.

The upper surface of the resin layer LR may be formed to correspond tothe upper surface of the plate GL. The flatness of the upper surface ofthe resin layer LR may be improved by the plate GL, and thus, thesurface quality of the display module DM disposed on the resin layer LRmay be increased. The thickness of the resin layer LR may correspond tothe first thickness D1 of the separation space SS.

FIG. 18C shows the separating of the plate GL from the resin layer LRafter the resin layer LR is formed on the support module SM (S5). As anexample, the support module SM on which the resin layer LR is formed maybe separated from the mold MD on which the plate GL is disposed.

An upper surface SM-Ua of the bent portion of the support module SM maycorrespond to the upper surfaces SP-2-U and SP-3-U (refer to FIG. 6) ofthe second and third portions SP-2 and SP-3 (refer to FIG. 6) of thefirst support bars SP-a. A length from the upper surface SM-Ua of thebent portion of the support module SM to the resin layer LR may bereferred to as a second thickness D2.

FIG. 18D shows the disposing of the display module DM on the resin layerLR separated from the plate GL (refer to FIG. 18C) to manufacture therollable display device DD (S6). As an example, the display module DMmay be attached to the resin layer LR through a lamination process.

The upper surface DM-U of the display module DM may be disposed at aposition that is the same as a position at which the upper surface SM-Uaof the bent portion of the support module SM is disposed when viewed incross-section. In other words, the thickness of the display module DMmay be substantially the same as the second thickness D2, however, itshould not be limited thereto or thereby. The surface quality of thedisplay module DM may be increased by the resin layer LR formed on theupper surface SM-U of the support module SM that is uneven or has thegap.

FIG. 19 shows the disposing of the support module SM on the mold MD todefine the separation space SS between the support module SM and theplate GL among the manufacturing method of the rollable display device.

The manufacturing method of the rollable display device may furtherinclude disposing a spacer SC on the plate GL before the disposing ofthe support module SM. The spacer SC may be disposed on the uppersurface of the plate GL to be adjacent to an edge of the plate GL. Thespacer SC may support the upper surface SM-U of the support module SM.

The spacer SC may have a thickness corresponding to the thickness D1 ofthe separation space SS. The thickness of the resin layer LR may beadjusted by adjusting the thickness of the spacer SC.

The spacer SC may include the same material as the resin layer LR. Theresin layer LR may be formed by curing the resin filled in theseparation space SS in a state where the spacer SC is included in theresin.

FIGS. 20A to 20C are perspective views showing the manufacturing methodof the rollable display device according to an embodiment of the presentdisclosure. FIG. 20D is a cross-sectional view showing the manufacturingmethod of the rollable display device according to an embodiment of thepresent disclosure. The manufacturing method of the rollable displaydevice may further include disposing a first dam portion DAM1 and asecond dam portion DAM2 on the mold MD.

FIG. 20A is a perspective view showing the disposing of the first damportion DAM1 on the mold MD on which the support module SM is disposed.The first dam portion DAM1 may be provided in plural, and the first damportions DAM1 may be disposed on the mold MD.

The first dam portions DAM1 may extend in the first direction DR1substantially parallel to the direction in which the support bars SPextend. The first dam portions DAM1 may support one end and the otherend of the support module SM in the second direction DR2. The first damportions DAM) may be spaced apart from each other with the supportmodule SM interposed therebetween in the second direction DR2. In otherwords, the first dam portions DAM1 may be disposed at opposite sides ofthe support module SM in the second direction DR2.

The first dam portions DAM1 may be coupled with the mold MD, however,they should not be limited thereto or thereby. The first dam portionsDAM1 may be disposed on and may be in contact with the mold MD andshould not be particularly limited as long as the first dam portionsDAM1 may support the support module SM.

The first dam portions DAM1 may prevent the resin filled in theseparation space SS (refer to FIG. 20D) from leaking to the outside ofthe support module SM. In the manufacturing process of the rollabledisplay device, the first dam portions DAM1 may allow the resin to besufficiently filled in the separation space SS (refer to FIG. 20D) andmay prevent the resin from being wasted.

At least one dam portion among the first dam portions DAM1 may beprovided with a hole HO therethrough. The hole HO may pass through thefirst dam portion DAM1. The hole HO may be connected to the separationspace SS (refer to FIG. 20D) between the plate GL and the support moduleSM. Accordingly, the resin may be injected through the hole HO, and theresin may be filled in the separation space SS (refer to FIG. 20D) afterpassing through the hole HO.

FIG. 20B is a perspective view showing the disposing of the second damportion DAM2 on the mold MD on which the first dam portion DAM1 isdisposed. The second dam portion DAM2 may be provided in plural, and thesecond dam portions DAM2 may be disposed on the mold MD.

The second dam portions DAM2 may extend in the second direction DR2crossing the first direction DR1 in which the first dam portions DAM1extend. The second dam portions DAM2 may support the lower surface ofthe support module SM, which is substantially parallel to the surfaceformed by the first direction DR1 and the second direction DR2. Thesecond dam portions DAM2 may be spaced apart from each other in thefirst direction DR1. For example, the second dam portions DAM2 may beprovided on opposite sides of the support module SM in the firstdirection DR1.

The second dam portions DAM2 may prevent the resin filled in theseparation space SS (refer to FIG. 20D) from leaking to the outside ofthe support module SM. The second dam portions DAM2 may prevent thesupport module SM from shaking in the manufacturing process of therollable display device.

The second dam portions DAM2 may be coupled with the first dam portionsDAM1, however, they should not be limited thereto or thereby. Accordingto an embodiment of the present disclosure, the second dam portions DAM2may be disposed on the first dam portions DAM1 to make contact with thefirst dam portions DAM1 or may be directly coupled with the mold MD.However, the second dam portions DAM2 should not be particularly limitedas long as the second dam portions DAM2 may support the support moduleSM.

FIG. 20C is a perspective view showing the filling of the resin in theseparation space SS after the first dam portions DAM1 and the second damportions DAM2 are disposed. FIG. 20D is a cross-sectional view showingthe process of FIG. 20C. In FIG. 20D, for the convenience ofexplanation, the support module SM and the plate GL facing andoverlapping one side surface of the first dam portion DAM1, which issubstantially parallel to the first direction DR1 and the thirddirection DR3, are indicated by a dotted line.

The resin LR-a may be provided to the first dam portion DAM1 to beinjected into the hole HO. A direction to which the resin LR-a isprovided is indicated by a reference numeral of 120 in FIG. 20C.Referring to FIGS. 20c and 20D, the resin LR-a may be injected into theseparation space SS provided between the plate GL and the support moduleSM, which is connected to the hole HO, after passing through the hole HOand may be filled in the separation space SS. When the resin is curedafter being sufficiently filled in the separation space SS, the resinlayer LR may be formed as shown in FIG. 18B.

According to the rollable display device of the present disclosure, thesurface quality of the display module may be increased by the supportmodule, the display module disposed on the support module, and the resinlayer disposed between the support module and the display module. Inaddition, since the driving axis of the support module is provided tocoincide with the neutral plane of the display module when viewed incross-section, the degree to which the display panel included in thedisplay module is compressed or tensioned by the external stress may bereduced, and the damage to the display panel may be prevented.

According to the manufacturing method of the rollable display device,since the resin layer that provides the flat upper surface is formed onthe support module and the display module is disposed on the resinlayer, the surface quality of the display module of the rollable displaydevice may be increased. Since the manufacturing method of the rollabledisplay device includes the disposing of the plate having the flat uppersurface, the flatness of the resin layer formed between the supportmodule and the plate may be improved. Since the manufacturing method ofthe rollable display device further includes the disposing of the damportions, the support module may be fixed to prevent the support modulefrom moving in the manufacturing process, and thus, the resin may beprevented from leaking to the outside of the support module.

Although the embodiments of the present disclosure have been described,it is understood that the present disclosure should not be limited tothese embodiments but various changes and modifications can be made byone ordinary skilled in the art within the spirit and scope of thepresent disclosure as hereinafter claimed.

Therefore, the disclosed subject matter should not be limited to anysingle embodiment described herein.

What is claimed is:
 1. A rollable display device, comprising: a supportmodule; a display module disposed on the support module and comprising adisplay area and a non-display area adjacent to the display area; and aresin layer disposed between the support module and the display module,the display module comprising a display panel comprising a plurality ofpixels, the support module comprising: a plurality of support barsextending in a first direction and arranged in a second directioncrossing the first direction, wherein the support bars are spaced apartfrom each other; and a plurality of hinges disposed between the supportbars and coupled with the support bars disposed adjacent thereto, andwherein each of the support bars is rotatably coupled with the hingeswith respect to a driving axis extending in the first direction, and thedriving axis penetrates the display panel when viewed in across-section.
 2. The rollable display device of claim 1, wherein aneutral plane of the display module is defined in the display panel at asame position as the driving axis when viewed in the cross-section. 3.The rollable display device of claim 1, wherein the resin layer has amodulus equal to or greater than about 1 kPa and equal to or less thanabout 50 MPa.
 4. The rollable display device of claim 1, wherein each ofthe support bars comprises a coupling portion, the coupling portion isinserted into a coupling recess in each of the hinges, and the couplingportion of each of the support bars move within the coupling recess. 5.The rollable display device of claim 1, wherein the support modulefurther comprises a sub-support bar extending in the first direction anddisposed between a pair of the support bars, and the sub-support bar iscoupled with the hinges connected to the pair of the support bars. 6.The rollable display device of claim 1, wherein each of the support barshas a width in the second direction and the widths of the support barsare different from each other.
 7. The rollable display device of claim6, wherein a difference in width between the support bars adjacent toeach other is constant.
 8. The rollable display device of claim 6,wherein the support module comprises a rolling area and a peripheralarea adjacent to the rolling area, the support module is in a flat stateor in a rolled state depending on whether the support module is rolledwith respect to a rolling axis spaced apart from the driving axis, alength of the rolling area of the support module defined in the seconddirection in the flat state satisfies the following Equation 1 of${L = {{x \cdot a} + \frac{x \cdot {b\left( {x - 1} \right)}}{2}}},$ anouter diameter of the support module in the rolled state satisfies thefollowing Equation 2 of D=(√{square root over (2)}+1)·{a+(5+x)b}, Ldenotes the length of the rolling area of the support module, D denotesthe outer diameter of the support module, x denotes a number of thesupport bars, a denotes a smallest width among the widths of the supportbars, and b denotes a difference in width between the support barsadjacent to each other.
 9. The rollable display device of claim 1,wherein the support module further comprises a plurality of bondingportions filled in a separation space between the support bars.
 10. Therollable display device of claim 9, wherein the bonding portions areprovided integrally with the resin layer.
 11. The rollable displaydevice of claim 9, wherein the support bars comprise surfaces that arein contact with the bonding portions, and at least a portion of thesurfaces comprises a curved surface.
 12. The rollable display device ofclaim 1, wherein the support module further comprises a plurality ofmagnets inserted into at least one of the support bars.
 13. The rollabledisplay device of claim 12, wherein the magnets are spaced apart fromthe display area in a plane view.
 14. The rollable display device ofclaim 1, wherein the display module further comprises: a window disposedon the display panel; and a protective layer disposed between thedisplay panel and the resin layer, wherein a neutral plane is definedbetween a lower surface of the display panel and an upper surface of thedisplay panel.
 15. The rollable display device of claim 1, furthercomprising: a flexible circuit board electrically connected to thedisplay panel; and a main circuit board disposed on a lower surface ofthe support module, the support bars comprising: first support barsoverlapping the display area and connected to each other; and a secondsupport bar connected to one first support bar disposed at an outermostposition in the second direction among the first support bars, andwherein the main circuit board is spaced apart from the first supportbars in a plane view and overlaps the second support bar, and theflexible circuit board surrounds at least a portion of the secondsupport bar and is electrically connected to the main circuit board. 16.The rollable display device of claim 15, wherein widths of the firstsupport bars, which are defined in the second direction, increase as adistance from the second support bar decreases.
 17. The rollable displaydevice of claim 15, further comprising a case spaced apart from thedisplay area and accommodating the flexible circuit board and the maincircuit board.
 18. A method of manufacturing a rollable display device,comprising; disposing a plate on a mold; disposing a support module onthe mold, wherein a space is provided between the support module and theplate; filling a resin in the space; curing the resin to form a resinlayer; separating the plate from the resin layer; and disposing adisplay module on the resin layer from which the plate is separated. 19.The method of claim 18, further comprising coating a primer on thesupport module before the disposing of the support module.
 20. Themethod of claim 18, further comprising disposing a spacer supporting thesupport module on the plate after the disposing of the plate.
 21. Arollable display device, comprising: a support module comprising aplurality of support bars and a plurality of hinges; a display moduledisposed on the support module; and a resin layer disposed between thedisplay module and the support module, wherein the plurality of supportbars extended in a first direction and arranged in a second directioncrossing the first direction, and the plurality of hinges connectingadjacent support bars to each other, wherein widths of the support barsare different from each other.
 22. The rollable display device of claim21, wherein widths of the support bars increase from a first side of thedisplay module to a second side of the display module.
 23. The rollabledisplay device of claim 21, wherein the support module further comprisesa plurality of sub-support bars connected to the hinges.
 24. Therollable display device of claim 21, wherein the resin layer overlaps agap between adjacent support bars.